Causal filter

最新推荐文章于 2025-09-16 00:33:19 发布

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#filter #output #processing #signal #input

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本文介绍了信号处理中因果滤波器的概念，这类滤波器属于线性和时不变系统，其输出仅依赖于过去的和当前的输入。文章还讨论了如何通过缩短或时间平移非因果脉冲响应来创建可实现的滤波器。

In signal processing , a causal filter is a linear and time-invariant causal system . The word causal indicates that the filter output depends only on past and present inputs. A filter whose output also depends on future inputs is acausal . A filter whose output depends only on future inputs is anti-causal . Systems (including filters) that are realizable (i.e. that operate in real time ) must be causal because such systems cannot act on a future input. In effect that means the output sample that best represents the input at time $t,$ comes out slightly later. A common design practice is to create a realizable filter by shortening and/or time-shifting a non-causal impulse response. If shortening is necessary, it is often accomplished as the product of the impulse-response with a window function .